Motor driven door assemblies are used in many applications, and are especially useful where the door's weight or position makes it difficult for a user to manually open and close the door. Known motor driven door assemblies generally arrange the motor at the top of the door, where a drive shaft of the motor is connected to the door through an arm configured to move along the draft shaft. As the drive shaft rotates about an axis perpendicular to the axis of rotation of the door's pivot, the arm's translation motion along the drive shaft causes the door to rotate about its pivot. However, in such an arrangement, the top mounted motor and arm assembly are in plain view, which is undesirable for aesthetic reasons. In addition, the exposed motor and arm assembly take up space above the door, are more prone to damage and dirt buildup, and may present a safety hazard. FIG. 10 shows an example of a prior art door assembly 100, which is mounted in a door frame 102 between adjacent walls 104. A top mounted motor 106 includes a drive shaft 108 that rotates about an axis X, which is perpendicular to an axis Y about which the door 110 rotates. As the drive shaft 108 of the motor 106 rotates, a transmission element 114 moves along the drive shaft 108 and coverts the rotary motion of the motor 106 to actuate an arm 116 that drives the door 110 open or closed about its rotational axis Y. While such a top mounted motor and arm assembly may be sufficient for non-commercial or light weight doors, its effectiveness decreases for heavier doors such as those used in medical radiation treatment rooms, which require special shielded doors that typically weigh 10,000-20,000 lbs, and up to 200,000 lbs.
Other known motor driven door assemblies require the motor to be firmly secured within the room's cement foundation or ceiling. Such known assemblies have the disadvantage that the motor assembly must be installed at the time the foundation or ceiling material (such as cement) is set, or the foundation or ceiling material must be removed and re-set if the motor is installed after the room is initially built.
A need exists for a motor driven door assembly that is suitable for use with heavy doors, does not require the use of a top mounted motor and arm, alleviates the problems associated with exposed motors and hinges, and can be easily installed without removal and re-pouring of the foundation or ceiling cement.